Last month we discussed the clutch and bellhousing portion of a four-speed installation, while this month we will continue on to discuss shifters and floorboards. From '64-67, GM used the same shift linkage for all Chevelles and El Caminos, but the shift handle had slight differences. The handles used for four-speed cars with a bench seat had a special curve to it, as did the handle used in all '67 applications. These shifters were mounted directly to the tailshaft of the transmission and utilized a pull-up on the handle for the reverse lockout. On '64-67 four-speed cars, a neutral safety switch was not used, and the backup light switch was mounted below the shifter and had a small rod that attached to the reverse linkage. To accommodate the shifter, GM used a special hump that was tack-welded to the floorboard then sealed with strip-caulk. There were actually two different humps used in '64-67, one for use with console, and one for use without a console. The non-console hump for '64-65 had a simple boot and retainer around the shift handle, but in '66-67, GM used a larger chrome die-cast bezel, which fit over the carpet. Fortunately, the floor humps are available in the reproduction marketplace, but the '66-67 non-console retainer is not available, and can be difficult to find.
In '68-72, GM changed over to a different style of shifter. The shifter was mounted to a bracket, which curved down under the transmission and mounted directly to a plate that was welded onto the crossmember. The shifter also had two support rods, one that dropped down to the crossmember and another that mounted with a bushing to the tailhousing of the transmission. In '68-72 Chevelles and El Caminos, GM finally began the use of a neutral safety switch. That switch was mounted to the clutch pedal and would allow the engine to turn over only when the clutch pedal was pushed in. The backup light switch was mounted to the steering column just like in an automatic column shift car, except the four-speed switch had only two prongs and was much smaller. The shifter had a reverse lockout linkage that connected to the steering column and operated the mechanism inside the column for the backup switch and also locks the steering wheel when the car is in reverse and the key is removed. The floor hump for use with a console had an elongated shifter hole with a boot and steel retainer, which was covered by a plastic tunnel that connected to the console. The non-console hump was a square shape and had a die-cast retainer for the boot, which fit on top of the carpet. All of these pieces for '68-72 are available reproduction with the exception of the backup and neutral safety switches.
The biggest problem is knowing where the floor hump mounts. There are a couple of ways to go about this task. One is to mount up the engine and transmission with the shifter (minus the handle), remove the crossmember, and locate and drill a hole in the place where the shifter will go through the floorboard. Once that is accomplished, you can cut away the sheetmetal to make a large enough hole for the floor hump to fit. Another method is to use the console. If you know exactly where the console mounts, you can locate the position of the shift handle and from there, position the floor hump. The best way to locate the position of the hump is to get a stock piece of floorboard with the four-speed hump already installed and use it as a template. This method makes things easy since the stock floorboard will usually have the floor hump, console brackets, and bucket seat brackets already installed and you can find the locations of all three if you decide to go that route. The problem is finding these floorboards. You can always scrounge around for them, but we also offer them on a loan basis. Next month we will discuss the 700R4 installation. -Dick
To contact the author, please call or write him at True Connections3848 Pierce St.Dept. SCRiverside, CA 92503(800) 600-4144www.true-connections.com